Thermal-fluid characterization and performance enhancement of direct absorption molten salt solar receivers

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018.

Bibliographic Details
Main Author: Tetreault-Friend, Melanie
Other Authors: Alexander H. Slocum and Emilio Baglietto.
Format: Thesis
Language:eng
Published: Massachusetts Institute of Technology 2018
Subjects:
Online Access:http://hdl.handle.net/1721.1/119037
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author Tetreault-Friend, Melanie
author2 Alexander H. Slocum and Emilio Baglietto.
author_facet Alexander H. Slocum and Emilio Baglietto.
Tetreault-Friend, Melanie
author_sort Tetreault-Friend, Melanie
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description Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018.
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spelling mit-1721.1/1190372019-04-12T22:53:10Z Thermal-fluid characterization and performance enhancement of direct absorption molten salt solar receivers Tetreault-Friend, Melanie Alexander H. Slocum and Emilio Baglietto. Massachusetts Institute of Technology. Department of Nuclear Science and Engineering. Massachusetts Institute of Technology. Department of Nuclear Science and Engineering. Nuclear Science and Engineering. Thesis: Ph. D., Massachusetts Institute of Technology, Department of Nuclear Science and Engineering, 2018. This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections. Cataloged from student-submitted PDF version of thesis. Includes bibliographical references (pages 155-160). This thesis presents an in-depth thermal-fluid analysis of direct absorption molten salt solar receivers. In this receiver concept, an open tank of semi-transparent liquid is directly irradiated with concentrated sunlight, where it is absorbed volumetrically and produces internal heat generation. The intensity distribution of the internal heating depends on the optical properties of the absorber liquid and the dimensions of the receiver. This heating results in a combination of thermal stratification and radiation-induced natural convection in the receiver, which govern the general thermal-fluid behavior and performance of the system. Direct absorption requires molten salts to be contained in open tanks directly exposed to the environment; consequently, the liquid absorber experiences thermal losses to the environment which reduces absorption efficiency and produces large temperature gradients immediately below the exposed liquid surface. The thesis presents an apparatus that allows for the precise measurement of light attenuation in high temperature, nearly transparent liquids. The apparatus is used to measure and characterize the absorption properties of the 40 wt. % KNO₃:60 wt. % NaNO₃ binary nitrate and the 50 wt. % KCl:50 wt. % NaCl binary chloride molten salt mixtures. The analytical model of the thermal stratification, radiation-induced convection, and radiative cooling effects highlights the key parameters and conditions for optimizing the thermal-fluid performance of the receiver. Computational fluid dynamics and heat transfer modeling of the CSPonD Demonstration prototype of a direct absorption molten salt solar receiver provide further insight into its performance. The findings from the analytical and computational analyses give motivation to create a new cover design for open tanks of molten salts consisting of floating hollow fused silica spheres. The cover concept is demonstrated experimentally and the analysis shows the cover's ability to reduce thermal losses by 50%. by Mélanie Tétreault-Friend. Ph. D. 2018-11-15T15:52:02Z 2018-11-15T15:52:02Z 2018 2018 Thesis http://hdl.handle.net/1721.1/119037 1059514399 eng MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission. http://dspace.mit.edu/handle/1721.1/7582 178 pages application/pdf Massachusetts Institute of Technology
spellingShingle Nuclear Science and Engineering.
Tetreault-Friend, Melanie
Thermal-fluid characterization and performance enhancement of direct absorption molten salt solar receivers
title Thermal-fluid characterization and performance enhancement of direct absorption molten salt solar receivers
title_full Thermal-fluid characterization and performance enhancement of direct absorption molten salt solar receivers
title_fullStr Thermal-fluid characterization and performance enhancement of direct absorption molten salt solar receivers
title_full_unstemmed Thermal-fluid characterization and performance enhancement of direct absorption molten salt solar receivers
title_short Thermal-fluid characterization and performance enhancement of direct absorption molten salt solar receivers
title_sort thermal fluid characterization and performance enhancement of direct absorption molten salt solar receivers
topic Nuclear Science and Engineering.
url http://hdl.handle.net/1721.1/119037
work_keys_str_mv AT tetreaultfriendmelanie thermalfluidcharacterizationandperformanceenhancementofdirectabsorptionmoltensaltsolarreceivers