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Analysis of atmospheric influences on ratio thermography for solar tower systems

Englin, Albin (2022) Analysis of atmospheric influences on ratio thermography for solar tower systems. Master's, Linköping University.

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Abstract

The knowledge of temperature and emissivity of the receiver are both critical for a solar tower power plant, in order to guarantee an efficient operation of the thermal receiver on the one hand, while monitoring any degradation of the receiver coating on the other hand. To make these measurements, a new thermographic system is currently being developed, using a multispectral camera working in the short wavelength infrared spectrum. This system applies the principle of ratio thermography, using a couple of narrow bandpass filters centered on atmospheric water absorption bands, at 1.4 and 1.9 µm, to reduce the influence of solar reflections on the measurement signal, making it sensitive to atmospheric conditions. In this thesis, a batch simulation approach is used to identify boundary atmospheric and operating conditions necessary to achieve temperature errors below 2 %, minimizing the influence of solar reflection. Furthermore the influence of atmospheric parameters on the sensitivity of ratio thermography is analyzed, in particular the validity of the gray body assumption. It is shown that the atmosphere has a critical influence on the measurement accuracy. A humid atmosphere and/or high zenith angle is necessary for making accurate measurements. Furthermore only receiver temperatures above 450°C could be measured for the current system configuration, regardless of atmospheric conditions. Assuming negligible solar reflections, the validity of the gray body assumption is shown to be sensitive to the precipitable water vapor. A model based atmospheric compensation is therefore required to further improve the accuracy of ratio thermography.

Item URL in elib:https://elib.dlr.de/189696/
Document Type:Thesis (Master's)
Title:Analysis of atmospheric influences on ratio thermography for solar tower systems
Authors:
AuthorsInstitution or Email of AuthorsAuthor's ORCID iD
Englin, AlbinSF-QLFUNSPECIFIED
Date:3 October 2022
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Number of Pages:91
Status:Published
Keywords:Concentrated solar power, Ratio thermography, Shortwave infrared, gray body assumption, Atmospheric compensation
Institution:Linköping University
Department:Department of Mathematics
HGF - Research field:Energy
HGF - Program:Materials and Technologies for the Energy Transition
HGF - Program Themes:High-Temperature Thermal Technologies
DLR - Research area:Energy
DLR - Program:E SW - Solar and Wind Energy
DLR - Research theme (Project):E - Condition Monitoring
Location: Köln-Porz
Institutes and Institutions:Institute of Solar Research > Qualifizierung
Deposited By: Caron, dipl.-Ing. Simon
Deposited On:09 Nov 2022 09:30
Last Modified:11 Nov 2022 17:05

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