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Monitoring of mirror and sensor soiling with TraCS for improved quality of ground based irradiance measurements

Wolfertstetter, Fabian and Pottler, Klaus and Geuder, Norbert and Affolter, Roman and Merrouni, Ahmed and Mezrhab, Ahmed and Pitz-Paal, Robert (2013) Monitoring of mirror and sensor soiling with TraCS for improved quality of ground based irradiance measurements. SolarPACES, 17-20 Sept 2013, Las Vegas, USA.

Full text not available from this repository.

Abstract

Meteorological stations for solar irradiance measurements are mainly utilized for resource assessment of possible sites for future solar power plants and for thermal efficiency calculation and control of operating power plants. These stations consist of a solar tracker, two pyranometers and a pyrheliometer (MHP) for irradiance measurements. The accuracy of the MHP instrumentation is usually specified to be better than 2 % if cleaned on a daily basis. However, soiling frequently exceeds other error influences significantly, reducing irradiance values and accuracy. Due to the high sensitivity to soiling shown by pyrheliometers, especially DNI measurements are affected. Reductions of measured DNI values exceeding 25 % in only a few weeks are not unusual. In order to improve this situation, the soiling level of each individual sensor can be determined by following a special sequence of sensor cleaning and brief breaks combined with a close examination of the sensor responses. This allows for an approximate post processing correction of the irradiance data measured since the last cleaning (if recent). The corrections applied are cross-checked by means of an improved version of the TraCS asset. It can be used to control the sensor soiling correction procedure. The TraCS’s improvement consists in rotating the mirror within its plane with the pyrheliometer thus scanning its surface instead of just viewing the same small spot on the mirror. Hence, a better accuracy of the mirror soiling level is achieved by deriving more reliable average values. Finally, the results of an examination of sensor soiling rates at several meteorological stations set up in the MENA region and cleaned following the described protocol is presented. This gives an idea about the range of regional differences in soiling rates to be expected in the North African region.

Item URL in elib:https://elib.dlr.de/86025/
Document Type:Conference or Workshop Item (Speech)
Title:Monitoring of mirror and sensor soiling with TraCS for improved quality of ground based irradiance measurements
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Wolfertstetter, Fabianfabian.wolfertstetter (at) dlr.deUNSPECIFIED
Pottler, KlausCSP ServicesUNSPECIFIED
Geuder, NorbertCSP ServicesUNSPECIFIED
Affolter, RomanCSP ServicesUNSPECIFIED
Merrouni, AhmedUniversite Mohammed I OujdaUNSPECIFIED
Mezrhab, AhmedUniversite Mohammed Premier OujdaUNSPECIFIED
Pitz-Paal, Robertrobert.pitz-paal (at) dlr.deUNSPECIFIED
Date:2013
Refereed publication:Yes
Open Access:No
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:DNI; soiling; meteorological data postprocessing; energy meteorology; cleaning sequence; meteorological measurements
Event Title:SolarPACES
Event Location:Las Vegas, USA
Event Type:international Conference
Event Dates:17-20 Sept 2013
Organizer:SolarPACES
HGF - Research field:Energy
HGF - Program:Renewable Energies
HGF - Program Themes:Concentrating Solar Systems (old)
DLR - Research area:Energy
DLR - Program:E SF - Solar research
DLR - Research theme (Project):E - Qualifizierung (old)
Location: Köln-Porz
Institutes and Institutions:Institute of Solar Research > Qualifizierung
Deposited By: Kruschinski, Anja
Deposited On:04 Dec 2013 11:03
Last Modified:08 May 2014 23:26

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