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Steady state calorimetric measurement of total hemispherical emittance of cylindrical absorber samples at operating temperature

Effertz, Timo and Pernpeintner, Johannes and Schiricke, Björn (2017) Steady state calorimetric measurement of total hemispherical emittance of cylindrical absorber samples at operating temperature. In: AIP Conference Proceedings, 1850, 020003-01-020003-07. Elsevier. 22nd SolarPACES Conference, 11.-14.Okt 2016, Abu Dhabi, UAE. DOI: 10.1063/1.4984327 ISBN 978-0-7354-1522-5 ISSN 0094-243X

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Official URL: http://aip.scitation.org/toc/apc/1850/1?expanded=1850

Abstract

At DLR’s QUARZ Center a test bench has been established to measure, using steady state calorimetric method, the total hemispherical emittance of cylindrical solar thermal absorber samples at temperatures up to 450 °C. Emittance measurement of solar absorber surfaces is commonly performed by direct-hemispherical reflectance measurements with spectrophotometers. However, the measurement of cylindrical samples with spectrophotometers can be considered still a challenge as integrating spheres, reference samples and calibration services by national metrology institutions are optimized for flat sample measurement. Additionally samples are typically measured at room temperature. The steady state calorimetric method does not rely on reference samples and the measurement is performed at operating temperature. In the steady state calorimetric method electrical power input used to heat the sample is equated to the radiative heat loss from a heated sample to the environment. The total emittance can be calculated using the Stefan-Boltzmann equation from radiative heat loss power, the defined sample surface area and measured surface temperature. The expanded uncertainty (k=2) of the total hemispherical emittance has been determined to ±13 % for a typical parabolic trough absorber sample at a temperature of 300 °C and a heating power of 100 W. The test bench was validated by the measurement of three samples with the spectrophotometer and the steady state calorimetric method.

Item URL in elib:https://elib.dlr.de/108843/
Document Type:Conference or Workshop Item (Speech)
Title:Steady state calorimetric measurement of total hemispherical emittance of cylindrical absorber samples at operating temperature
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Effertz, TimoTimo.Effertz (at) dlr.dehttps://orcid.org/0000-0002-9152-4656
Pernpeintner, JohannesJohannes.Pernpeintner (at) dlr.deUNSPECIFIED
Schiricke, BjörnBjoern.Schiricke (at) dlr.deUNSPECIFIED
Date:June 2017
Journal or Publication Title:AIP Conference Proceedings
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In SCOPUS:Yes
In ISI Web of Science:No
Volume:1850
DOI :10.1063/1.4984327
Page Range:020003-01-020003-07
Publisher:Elsevier
ISSN:0094-243X
ISBN:978-0-7354-1522-5
Status:Published
Keywords:Total Hemispherical Emittance, Emittance, Calorimetric Measurement, Steady State, Emissionsgrad, Hemisphärischer Emissionsgrad,
Event Title:22nd SolarPACES Conference
Event Location:Abu Dhabi, UAE
Event Type:international Conference
Event Dates:11.-14.Okt 2016
Organizer:SolarPACES
HGF - Research field:Energy
HGF - Program:Renewable Energies
HGF - Program Themes:Concentrating Solar Thermal Technology
DLR - Research area:Energy
DLR - Program:E SF - Solar research
DLR - Research theme (Project):E - Impact of Desert Environment (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Solar Research > Qualifizierung
Deposited By: Kruschinski, Anja
Deposited On:05 Dec 2016 14:31
Last Modified:31 Jul 2019 20:06

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